A Baltimore writer missing in Libya since March has been seen in a prison in Tripoli, his mother and a U.S. congressman said Thursday.

Matthew VanDyke, a photojournalist and writer, traveled to Libya in early March to write about the revolt against Moammar Gadhafi. His mother, Sharon VanDyke, last heard from him on March 12, reported The Baltimore Sun. A friend had told her in April that he believed VanDyke was captured by Gadhafi forces near the city of Brega.

Jaime Lennon, a spokeswoman for Maryland Rep. C.A. Dutch Ruppersberger, said Thursday there have been two separate sightings of the 31-year-old in a Tripoli prison, according to The Associated Press.

Sharon VanDyke said she was told her son is in good health.

"I am trying to get more information, but I will do nothing to jeopardize Matthew," she told The Baltimore Sun. "The most important part of this information is that he is in good health. He is tall and thin and didn't have 20 pounds he could lose. This is a real sense of relief."

The State Department, who in April listed VanDyke among several other Americans missing in Libya, was working to confirm the sightings of him, said Ruppersberger's spokesman.

His mother wrote to friends on Thursday, "It may startle some of you that I think prison is a great place to be. The exciting part is that finally Matthew has been located," reported The Sun. She said government officials will be working to bring him home, and she has no plans to travel to Libya.

Sharon VanDyke went to Turkey in May to distribute photos of her son to the Libyan embassy there.

Matthew VanDyke has traveled extensively throughout the Middle East, and has covered events there as a reporter and a photojournalist. Last year, he went on a six-month motorcycle trip through Iraq, Iran and Afghanistan, according to The Sun.

He has been working on a book about his travels, and his trip to Libya was to be the final chapter, his family said.

An earlier version of this story incorrectly stated that Rep. Ruppersberger’s spokesman had commented on this matter.